Can't Stand the Pressure: The Association Between Unprotected Standing, Walking, and Wound Healing in People With Diabetes

Fibreglass Total Contact Casting, Removable Cast Walkers, and Irremovable Cast Walkers to Treat Diabetic Neuropathic Foot Ulcers: A Health Technology Assessment

BACKGROUND

Diabetic neuropathic foot ulcers are a risk factor for lower leg amputation. Many experts recommend offloading with fibreglass total contact casting, removable cast walkers, and irremovable cast walkers as a way to treat these ulcers.

METHODS

We completed a health technology assessment, which included an evaluation of clinical benefits and harms, value for money, and patient preferences for offloading devices. We performed a systematic literature search on August 17, 2016, to identify randomized controlled trials that compared fibreglass total contact casting, removable cast walkers, and irremovable cast walkers with other treatments (offloading or non-offloading) in patients with diabetic neuropathic foot ulcers. We developed a decision-analytic model to assess the cost-effectiveness of fibreglass total contact casting, removable cast walkers, and irremovable cast walkers, and we conducted a 5-year budget impact analysis. Finally, we interviewed people with diabetes who had lived experience with foot ulcers, asking them about the different offloading devices and the factors that influenced their treatment choices.

RESULTS

We identified 13 randomized controlled trials. The evidence suggests that total contact casting, removable cast walkers, and irremovable cast walkers are beneficial in the treatment of neuropathic, noninfected foot ulcers in patients with diabetes but without severe peripheral arterial disease. Compared to removable cast walkers, ulcer healing was improved with total contact casting (moderate quality evidence; risk difference 0.17 [95% confidence interval 0.00-0.33]) and irremovable cast walkers (low quality evidence; risk difference 0.21 [95% confidence interval 0.01-0.40]). We found no difference in ulcer healing between total contact casting and irremovable cast walkers (low quality evidence; risk difference 0.02 [95% confidence interval -0.11-0.14]). The economic analysis showed that total contact casting and irremovable cast walkers were less expensive and led to more health outcome gains (e.g., ulcers healed and quality-adjusted life-years) than removable cast walkers. Irremovable cast walkers were as effective as total contact casting and were associated with lower costs. The 5-year budget impact of funding total contact casting, removable cast walkers, and irremovable cast walkers (device costs only at 100% access) would be $17 to $20 million per year. The patients we interviewed felt that wound healing was improved with total contact casting than with removable cast walkers, but that removable cast walkers were more convenient and came with a lower cost burden. They reported no experience or familiarity with irremovable cast walkers.

CONCLUSIONS

Ulcer healing improved with total contact casting, irremovable cast walkers, and removable cast walkers, but total contact casting and irremovable cast walkers had higher rates of ulcer healing than removable cast walkers. Increased access to offloading devices could result in cost savings for the health system because of fewer amputations. Patients with diabetic foot ulcers reported a preference for total contact casting over removable cast walkers, largely because they perceived wound healing to be improved with total contact casting. However, cost, comfort, and convenience are concerns for patients.

Real-Time Smart Textile-Based System to Monitor Pressure Offloading of Diabetic Foot Ulcers

BACKGROUND

The lifetime risk of developing a diabetic foot ulcer (DFU) is at least 25%. A DFU carries a 50% risk for infection and at least 20% of those receive some form of amputation. The most significant parameter that prevents or delays ulcer healing is high plantar pressure. To improve the patient's healing process, the DFU's plantar pressure should remain cumulatively low. Therefore, a tool that continuously measures the DFU loading, and provides real-time feedback can improve the healing outcome.

METHODS

We report the development of a system capable of continuously measuring the pressure, which could have applications to monitor DFU. The system contains a textile pressure sensor attached to a stretchable band, hardware that collects data and transmits them via Bluetooth to a phone, an app that gathers the data and stores them in the cloud, and a web dashboard that displays the data to the clinician. The sensor was characterized in vitro using the system, and the web-dashboard was developed and tested on simulated patient data.

RESULTS

We demonstrate the feasibility of developing the system and characterize the pressure response of the device. As a result, we demonstrate a viable method for monitoring DFU off-loading in real time.

CONCLUSIONS

The presented study demonstrates the feasibility to develop a simple, modular wearable system that opens up new possibilities for diabetic foot ulcer care by providing a way of monitoring the pressure under the ulcer in real time.

Differences in the daily activity of patients with diabetic foot ulcers compared to controls in their free-living environments

The aims of our study were to investigate multiple daily activity outcomes in patients with diabetic foot ulcers (DFU) compared to diabetic peripheral neuropathy (DPN) and diabetes (DM) controls in their free-living environments. We examined daily activity outcomes of 30 patients with DFU, 23 DPN and 20 DM. All patients wore a validated multi-sensor device for > 5 days (>22 hours per day) to measure their daily activity outcomes: steps, energy expenditure (kJ), average metabolic equivalent tasks (METs), physical activity (>3·0 METs) duration and energy expenditure, lying duration, sleep duration and sleep quality. We found that DFU patients recorded fewer median (interquartile ranges, IQR) daily steps [2154 (1621-4324)] than DPN [3660 (2742-7705)] and DM [5102 (4011-7408)] controls (P < 0·05). In contrast, DFU patients recorded more mean ± SD daily energy expenditure (kJ) (13 006 ± 3559) than DPN (11 085 ± 1876) and DM (11 491 ± 1559) controls (P < 0·05). We found no other differences in daily activity outcomes (P > 0·1). We conclude that DFU patients typically take fewer steps but expend more energy during their normal daily activity than DPN and DM controls. We hypothesise that the increased energy expenditure for DFU patients may be due to wound healing or an inefficient gait strategy. Further investigations into this energy imbalance in DFU patients may improve healing in future.

Smarter Sole Survival: Will Neuropathic Patients at High Risk for Ulceration Use a Smart Insole-Based Foot Protection System?

OBJECTIVE

This study examined adherence to alert-based cues for plantar pressure offloading in patients with diabetic foot disease.

METHOD AND DESIGN

Participants (n = 17) with in diabetic foot remission (history of neuropathic ulceration) were instructed to wear a smart insole system (the SurroSense Rx, Orpyx Medical Technologies Inc, Calgary, Canada) over a three-month period. This device is designed to cue offloading to manage unprotected sustained plantar pressures in an effort to prevent foot ulceration. A successful response to an alert was defined as pressure offloading, which occurred within 20 minutes of the alert onset. Patient adherence, defined as daily hours of device wear, was determined using sensor data and patient questionnaires. Changes in these parameters were assessed monthly.

RESULTS

Patients demonstrating increased adherence over the course of the study received more alerts (0.82 ± 0.31 alerts/hour) than patients whose adherence did not improve (0.36 ± 0.46 alerts/hour, P = .156). By the final stages of the study, participants who had received at least one alert every two hours were more adherent with offloading than participants who received fewer alerts (52.5 ± 4.1% vs 24.7 ± 22.4%, P = .043). Furthermore, duration of time from alert generation to successful offloading was significantly greater in the group receiving fewer alerts. This was measured in the third month with an effect size Cohen's d = 1.739, P = .043.

CONCLUSION

The results suggest a minimum number of alerts (one every two hours) is required for patients with diabetic neuropathy to optimally respond to offloading cues from a smart insole system.

Lace Up for Healthy Feet: The Impact of Shoe Closure on Plantar Stress Response

OBJECTIVE

This study examined the impact of shoe closure on plantar thermal stress response (TSR), which is known to be a surrogate of shear stress and skin perfusion. It is aimed to explore potential impact of shoe closure on increasing risk factors associated with plantar ulcers in people with diabetic peripheral neuropathy (DPN).

METHODS

Fifteen eligible subjects were enrolled. The left foot was used as a reference and fitted to a self-adjusted and habitual lace-tightening method by each subject. The right foot was used as a test closure and fitted into three lace closure conditions: loose, tight, and preset optimal closure (reel clutch, BOA technology). Thermal images were taken after 5 minutes of acclimatization (pre-trial) and immediately after 200 walking steps in each shoe closure condition (post-trial). TSR was calculated from the thermal images.

RESULTS

TSR was significantly higher in the test closure with loose (70.24%, P = .000) and tight (66.85%, P = .007) and lower (-206.53%, P = .000) in the preset optimal closure when compared to the reference closure. Only lace closure conditions affected TSR with no significant impact from age, BMI, and gender in our sample in a multivariable regression model.

CONCLUSION

The results from this study suggest that shoelace closure technique can have a profound effect on TSR. It therefore stands to reason that optimal lace closure may have an impact in reducing risk of plantar ulcers in people with DPN. Interestingly, results revealed that even a self-adjusted lace closure may not be necessarily optimal and a preset closure setting like reel clutch might ultimately be recommended to minimize risk. Further study is warranted to confirm or refute these interesting results.